Aspects of the present disclosure relate generally to wireless communication systems, and more particularly, to apparatus and methods for early transport format determination in wireless communications.
Wireless communication networks are widely deployed to provide various communication services such as telephony, video, data, messaging, broadcasts, and so on. Such networks, which are usually multiple access networks, support communications for multiple users by sharing the available network resources. One example of such a network is the UMTS Terrestrial Radio Access Network (UTRAN). The UTRAN is the radio access network (RAN) defined as a part of the Universal Mobile Telecommunications System (UMTS), a third generation (3G) mobile phone technology supported by the 3rd Generation Partnership Project (3GPP). The UMTS, which is the successor to Global System for Mobile Communications (GSM) technologies, currently supports various air interface standards, such as Wideband-Code Division Multiple Access (W-CDMA), Time Division-Code Division Multiple Access (TD-CDMA), and Time Division-Synchronous Code Division Multiple Access (TD-SCDMA). The UMTS also supports enhanced 3G data communications protocols, such as High Speed Packet Access (HSPA), which provides higher data transfer speeds and capacity to associated UMTS networks.
Generally, in W-CDMA voice traffic transmission, the network uses one out of multiple possible transport formats to send voice data to a user equipment (UE). Selection of a particular transport format depends on the data traffic conditions. In order to properly decode the received voice data, the UE needs to determine the transport format used by the network in transmitting the voice data. Currently, when the UE has to perform blind transport format detection (BTFD) in the absence of any information about the transport format used by the network during a transmission time interval (TTI), the UE waits until the entire signal transmission during the TTI is received, and then attempts to determine the transport format used by the network during that TTI.
Generally, the downlink signal transmitted from a base station and received by a mobile station may be represented as the desired signal convolved with a multi-path channel and added with noise and interference from other sources. For example, in a W-CDMA network, the downlink multi-path channel may cause inter-symbol-interference to the signal, and may prevent the mobile station from achieving a high data rate. To improve the signal-to-interference ratio for a mobile station, the energy of the signal may be increased to appropriate levels. However, increasing the energy of one mobile station increases the interference of that mobile station to other nearby mobile stations. As such, a radio communication system may determine a tradeoff among the requirements of different mobile stations sharing the same common channel. For example, a steady state condition may be reached when the signal-to-interference ratio (SIR) requirements for the mobile stations within a given radio communication system are satisfied by using power levels at each mobile station that are neither too high nor too low. Achieving such a steady state may require signal/noise power estimation at each mobile receiver so that signal-to-interference power levels are appropriately maintained.
As the demand for mobile broadband access continues to increase, research and development continue to advance the UMTS technologies not only to meet the growing demand for mobile broadband access, but to advance and enhance the user experience with mobile communications. Thus, in this case, there is a desire for improvements in determination of the transport format that is used during a TTI. Also, there is a desire for improved signal and/or noise power estimation at a mobile terminal.